U.S. Pat. No. 3,929,781, granted to applicants on Dec. 30, 1975 discloses a genus of penicillin and cephalosporin derivatives of the formula: ##STR2## in which R.sup.1 is --H, alkyl of 1 to 6 carbon atoms, aryl of 6 to 10 carbon atoms, or aralkyl of 7 to 12 carbon atoms;
R.sup.2 is --H or alkyl of 1 to 6 carbon atoms; PA1 R.sup.3 is --H, alkyl of 1 to 6 carbon atoms, monocyclic aryl of 6 to 10 carbon atoms, monocyclic aralkyl of 7 to 10 carbon atoms, --OH, --NH.sub.2 or --CO.sub.2 H; PA1 Y is ##STR3## wherein R.sup.4 is H, (lower) alkanoyloxy, ##STR4## R.sup.5 is --H, an alkali metal cation or the ammonium ion and N IS AN INTEGER FROM 0 TO 5, INCLUSIVE.
The subject matter of U.S. Pat. No. 3,929,781 was made the subject of a patent application filed in Japan in July 9, 1974 as Ser. No. 79041/1974 which was published Apr. 16, 1975, and in Great Britain filed on July 23, 1974, published June 30, 1976 as Ser. No. 1,441,345.